Effects of AC magnetic field on spin-exchange relaxation of atomic magnetometer

Abstract

By operating at high alkali-metal densities and in low magnetic fields, the spin-exchange relaxation of atomic magnetometers can be eliminated, allowing construction of ultra-high sensitive spin-exchange relaxation-free magnetometers. Significant AC magnetic fields are usually introduced in the magnetometer by the magnetic field modulation technique or the cell heater, whose effects on the spin-exchange relaxation have not been evaluated. In this paper, we study experimentally the spin-exchange relaxation rate as a function of the magnetic field frequency, the magnetic field amplitude and the spin-exchange rate in low magnetic fields. The experimental results indicate that for low atomic polarization the spin-exchange relaxation rate decays exponentially with the magnetic field frequency, and the reciprocal of the decay constant is proportional to the spin-exchange rate.